The development trend of SMT pcb assembly services
(2) of the solder paste printing technology. There is no doubt that the solder paste printing technology is the most revolutionary new technologies in the field of SMT equipment in recent years, successfully developed by the Swedish company MYDATA. It changed the traditional screen-printing mode, and apply the latest MY500 solder paste printing machine, the machine speed of 500 points per second on the circuit board pad slide, printing paste, as shown in Figure 3 is jet printing principle. Solder paste into the sealed pressure tank by a screw rod, then, by a lever to pressure. No stencil, it have many advantages, most notably the greatly reduced production conversion and delivery time. Calculator-like inkjet printer, the MY500 is divided into three parts: the printing machine itself, the print head and paste boxes, as well as offline programming software. Solder paste cartridge replacement is already fast, easy to like the inkjet printer replacement ink cartridges. Capacity is only 100 grams, however, paste packed in a sealed container, and almost no loss, the actual use of down very save. The MY500 without steel plate, cleaning agents, cleaning paper, paste mixer ..., models of diversity and the trial production of the heavy task of pressure, MY500 great help. MY500 is also known for its speed, which uses patented JetPrinting 500 points per second speed spray paste is 1,800,000 points per hour. With easy-to-use touch screen interface, touch screen located on the side of the printing machine operator to provide guidance in the process of setting jet printer.
The MY500 Aegis company Circuitcam offline data preparation software, directly from a variety of formats CAD file conversion and generate printing program programming efficiency is improved significantly. In the production process, you do not have to adjust the squeegee pressure, speed or other screen printing parameters. Because the program is fully controlled by software, you can adjust the amount of solder paste according to need, you can also control the solder paste amount of each component or individual pads, which can not be achieved in the traditional screen printing.
(3) printed circuit board at the bottom of the support tools. With the increasingly wide range of applications of the double sided PCB assembly at the bottom of the support tools on the press more and more attention. In particular, the flexible board is easy to bend, when the second side of the printed solder paste on board, and often need the bottom of the support, the common support of the fixed plate shown in Figure 4, using the length of the thimble to multi-point support. , Which support the way to a certain extent to solve the plate bending problem, but there will still be in the span between the large thimble plate loosening and local bending, there bad printing. The adjustable plate support a fixed mold scalable planar support (see Figure 5), and the flexibility to adapt to the shape of the bottom of the circuit board to support the PCB to achieve high-quality printing.
(4) and stable pressure control. Printing squeegee pressure exerted on the PCB has a great influence on the printing quality, especially the printing of fine pitch components. The past, a lot of automatic printing by adjusting the scraper downward journey to adjust the printing pressure, the disadvantages of this method is the size of the pressure level degree dependent on the template board, while the actual scraper moving, due to the ups and downs of the template surface, squeegee pressure floating, and sometimes may appear a great deviation in the road templates depression, a sharp decline in pressure in the protruding sharp rise. This may cause the print quality of the different locations are quite different in the same one on the PCB.